07 Yukon Trouble Starting After Refill - Code 496

[bigdaddymrp]

2007 GMC Yukon XL 1500 - 150k miles

 

Started at a gas station a few months ago. Filled tank, went to restart it and the engine turned over but never started. Completely drained battery trying this. Checked for compression, spark, and fuel. Was getting all three.

 

Exposed the throttle body, and manually opened the butterfly. Then it started after sputtering for a bit.

 

Since then, EVERY TIME I fill up, same thing, but I learned that fluttering the gas pedal will allow it to start sputtering and eventually start.

 

Haven't noticed a change in performance, only in starting.

 

If I leave it running while fueling, I'll notice all kinds of errors on the display, (stabilitrack disabled, etc.) but they go away after a few seconds.

 

Since then, I've been getting code #496. I bought a code reader so I can erase the code in case another code comes up. But it returns eventually, could be hours later, sometimes days.

 

After a little research, I'm guessing it might be the evap canister or the vent solenoid. Am I on the right track? Anyone know the part # of the vent solenoid, if that's the case? Dealership quoted $500 to fix this. And said that he's seen it get so bad that the gas tank could implode itself with so much negative pressure.

 

Any insight is greatly appreciated.